In downhill skiing, speed of descent can be controlled in a variety of ways, depending upon factors such as steepness of the slope, snow conditions, irregularities in the terrain, skill and strength of the skier, etc. A skilled skier can check speed by executing a series of turns in relatively rapid succession while maintaining a generally downward trajectory. A less skilled person may tend to ski laterally back and forth across the slope, minimizing the vertical component of the path and executing less frequent turns. Regardless of the level of skill of the skier, however, the condition of a particular area of terrain, unsatisfactory weather conditions, reduced visibility toward the end of the day and/or fatigue can make it difficult at times for a skier to maintain speed at a safe and comfortable level and/or to respond to an emergency condition or obstacle.
It has been proposed heretofore to provide downhill skis with devices for projecting one or more elements into the snow surface over which the skis are moving, in order to add resistance and reduce the speed of the skis. In the Smith U.S. Pat. No. 4,152,007, for example, brake elements are pivotally mounted at the trailing ends of the skis and are actuated by hydraulic cylinders mounted on the skis. A hand-operated hydraulic pump is mounted on a ski pole and can be operated by the skier who desires to reduce speed. The brake elements are pivoted downward by their respective cylinders and dig into the snow behind the skis to introduce resistance and reduce the speed of the skis. The Daniel U.S. Pat. No. 5,509,683 also has brake elements pivoted at the trailing ends of the skis. The brake elements of Daniel are actuated by electric motors driving linear screw shafts in much the same manner as the hydraulic cylinders of the above-mentioned Smith patent. The Rassman U.S. Publication 2009/0200772 discloses a device with pivoted braking elements, mounted either at the trailing ends of the skis or, if forward of the trailing ends, in straddling relation to the individual skis. In one embodiment of the Rassman device, the braking elements are actuated by a flexible cable connected to grips on the ski poles and operated somewhat in the manner of standard bicycle brakes. In another embodiment, the cables are operated by electric motors on the individual skis, operated by a wireless control carried by the skier.
The known devices have several significant shortcomings. For example, devices that are attached to the trailing ends of the skis can change the desired balance of the skis by adding extra weight at the trailing end extremities. Moreover, when the trailing end devices are actuated, they can make steering of the skis difficult by tending to hold the ski tails on a pre-existing path instead of allowing them to freely move laterally to enable the skier to change the direction of the skis. When seeking to reduce speed or to stop, the ability to change the direction of the skis relative to the fall line of the hill can be very important.
In some embodiments of the Rassman et al publication, while the braking elements are mounted forward of the ski tails, a pair of braking elements is arranged to straddle each of the skis. This increases the likelihood of the two skis becoming engaged during skiing to interfere with the skier's control and also provides exposed sharp edges that could result in injury in a fall.